Two-Stage Combustion for Low Emissions without Catalytic Convertors *

The concept of using two-stage combustion in a spark ignition engine has been tested in a single cylinder CFR engine. The engine was operated over an equivalence ratio range of 1.5 to 2.2 to evaluate the first stage of combustion. The product gas was analyzed for H₂, CO, CO₂, and hydrocarbons.

An atmospheric burner was operated with gasoline over the same equivalence ratio range of 1.5-2.2, and the resulting product gases were then burned in the CFR engine to test the second stage of combustion. Emissions of NO_x, HC and CO of 0.1, 0.1, and 5 gm/IHP-hr were measured respectively. The engine indicated efficiency for the two-stage mode was essentially the same as for the single-stage mode.